焚烧飞灰协同去除垃圾渗滤液纳滤膜浓缩液中CODCr的特性研究

城市生活垃圾焚烧飞灰和垃圾渗滤液膜浓缩液的环境无害化处置已成为目前行业和政府管理部门亟待解决的难题.遵循“以废治废”的研究思路，利用填料柱开展了生活垃圾焚烧飞灰去除NF（纳滤）膜浓缩液中COD_Cr的特性研究，重点研究了不同淋滤速率（40、60、80 mL/h）、填料层厚度（5、15、25 cm）条件下NF膜浓缩液中COD_Cr随淋滤时间的去除效果.结果表明:NF膜浓缩液中COD_Cr的去除主要依靠飞灰的吸附、化学沉淀以及截留作用；淋滤速率对NF膜浓缩液中COD_Cr的去除效果影响很小，COD_Cr去除率随填料层厚度增加而增大；当填料层厚度为15 cm、淋滤速率为60 mL/h时，飞灰对垃圾渗滤液纳滤膜浓缩液中COD_Cr的去除效果总体达到最佳，且相应灰渣的含盐量以及Pb、Zn、Cu、Cd、Cr的浸出毒性均显著降低.研究显示，最佳条件下飞灰对NF膜浓缩液COD_Cr去除率可达40%以上. 

Synergistic Removal Characteristics of Chemical Oxygen Demand from Nanofiltration Membrane Concentrated Leachate by Municipal Solid Waste Incineration Fly Ash

The environmentally sound disposal of municipal solid waste incineration (MSWI) fly ash and membrane concentrated leachate has become an urgent and difficult problem for industry and government agencies. Following the research idea of 'waste treatment by waste', this study focused on removal characteristics of chemical oxygen demand (COD_Cr) in nanofiltration (NF) membrane concentrate by using a MSWI fly ash-packed column. This work investigated the effect of leaching rate (40, 60 and 80 mL/h) and thickness of the packing layer (5, 15 and 25 cm) on the removal efficiency of COD_Cr at different leaching time. The results showed that the removal of COD_Cr in NF membrane concentrates mainly depended on the adsorption, chemical precipitation and retention of fly ash. The column filtration rate had little effect on the removal efficiency of COD_Cr in the membrane concentrated leachate, the removal rate of COD_Cr increased with increasing thickness of the packing layer. When the thickness of the packing was 15 cm and the leaching rate was 60 mL/h, the removal efficiency of COD_Cr in NF concentrates was the best. The salt content and leaching toxicity of Pb, Zn, Cu, Cd and Cr in the ash residue were both decreased significantly. Moreover, the study showed that the best removal percentage of COD_Cr was higher than 40%.